Db chores
DB now relies on vies in db. Views are setum un migrations, however schemas must be manually copied from README.md for two existing views.
Added features:
- Added subscriptions to db
- comments and videos now return username of author as well
- added profile pic url attribute of user
- allow to retrive video of specific authors
- allow to edit description and title and premium_status of video
- added views tracking (very dumb way)
- added support for multiple categories for video